Convert Lines per millimetre to Dots per centimetre

Convert Lines per millimetre (lp/mm) to Dots per centimetre (dpcm) instantly and accurately.

Conversion Formula

dpcm = lp/mm × 10

About Lines per millimetre

The line pair per millimetre (lp/mm) is the fundamental unit of spatial resolution in classical optics, characterising the resolving power of a lens, film emulsion, sensor, or microscope objective. A resolving power of N lp/mm means adjacent line pairs separated by 1/(2N) mm can be distinguished - derived from the Abbe diffraction limit (Ernst Abbe, 1873) and Rayleigh criterion (Lord Rayleigh, 1879). Film benchmarks at MTF50: Kodak Tri-X 400: 63 lp/mm; Fujifilm Velvia 50: 160 lp/mm; Kodak Technical Pan: 320 lp/mm. Lens benchmarks: Leica APO-Summicron-M 50 mm f/2 ASPH: ≈ 75 lp/mm at centre. CMOS sensor Nyquist frequency: for pixel pitch p mm, f_Nyquist = 1/(2p) lp/mm - a 4.63 µm pixel limits at ≈ 108 lp/mm. As a dimensional unit, 1 lp/mm = 25.4 LPI = 25.4 PPI exactly. 1 lp/mm = 25.4 PPI.

About Dots per centimetre

The dot per centimetre (dpcm) is the metric equivalent of DPI, defined as a CSS resolution unit in the W3C CSS Images Level 3 specification alongside dpi and dppx. A 96 DPI reference screen (CSS Media Queries Level 4 reference device) corresponds to 96/2.54 ≈ 37.795 dpcm. ITU-T T.4 (Group 3 facsimile, 1980) defines scan line density in metric units: standard resolution 3.85 lines/mm = 38.5 dpcm; fine resolution 7.7 lines/mm = 77 dpcm. ITU-T T.85 (JBIG compression) standardised these metric resolutions for cross-border interoperability. ISO 216 A4 scanned at 77 dpcm fine fax resolution yields 1617 pixels across page width. The CSS specification recommends dppx over dpcm for screen media queries, reserving dpcm for print stylesheets targeting metric-resolution printers. 1 dpcm = 2.54 DPI = 2.54 PPI exactly (since 1 in = 2.54 cm). 1 dpcm = 0.1 dot/mm.

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